Charles Guffey & John Rogers, Texas Tech University & Larry Hester, Teledyne Merla
A number of different methods of controlling beam pumping units are in use today and the important features of each are considered. Most of these controllers use the polish rod load (measured directly or by inference from the motor load) to determine the performance of the rods and pump downhole in the well. Whenever a variation in the rod load is seen indicating that the pump is not full of liquid, the controller shuts down the pump - usually for a fixed period of time. A new method which slows the pump motor by use of a variable frequency drive, allowing continuous operation, has been tested in West Texas. The advantages of this 11pumpdown18 method and preliminary results of the test program will be presented.